Abstract: In view of the differences in many aspects of the wireless power transfer system of electric vehicles, it is difficult to realize the interconnection between different ground transmitting terminals and vehicle receiving terminals, the low efficiency of vehicle charging, and even the existence of security risks in serious cases. This paper proposed a method to judge the interoperability of the electric vehicle wireless power transfer system based on three parameters. The vehicle loop detuning factor ξ, interoperability characteristic impedance δ and real part of ground impedance Re(Z_GA) were used to characterize the influence of different compensation networks and coupling coil parameters on system interoperability. The interoperability of electric vehicle wireless power transfer system was evaluated by judging whether the system meets the three parameter criterion. The correctness of the theory was verified by simulation and experiment. This method had a guiding role for the evaluation of wireless power transfer interoperability of electric vehicles.